Recently, fundus autofluorescence imaging (FAF: Fundus Auto-Fluorescence) has been receiving attention. PTL1 has disclosed that, in autofluorescence imaging, the fundus is illuminated with light around 550 nm as excitation light and light around 640 nm is received as autofluorescence caused by lipofuscin. A user may detect age-related macular degeneration or the like at an early stage by checking lipofuscin using a fundus image acquired as a result of this light reception.
In addition, PTL2 has disclosed that a subtraction image is generated by achieving matching for a plurality of fundus images using an optic disk portion and a blood vessel portion in the plurality of fundus images.